There are many different styles of tip retainer mechanisms on the market today for the purpose of retaining tips on adapters. In many of these arrangements, the tip is assembled on the adapter, a pin extends through holes in the tip and a transverse bore in the adapter to secure the tip to the adapter. In order to keep the pin from inadvertently coming out, a retainer is normally used to retain the pin in the assembled position. This retainer mechanism has been made of various shapes and sizes. For example, U.S. Pat. No. 3,801,210 issued Apr. 2, 1974 to Lloyd K. Heinold et al. teaches a retainer mechanism that has two wire clips molded in an elastomeric material When assembled, the spring clips provide a force to retain a rectangular bar in the respective holes. Another example is illustrated in U.S. Pat. No. 3,952,433 issued Apr. 27, 1976 to Lloyd K. Heinold et al. wherein a spring clip is substantially encapsulated by a cylindrical elastomeric member. When assembled, the spring clip applies a biasing force to a pin to hold the pin in its assembled position U.S. Pat. No. 3,997,989 issued Dec. 21, 1976 to V. A. Stepe teaches an arrangement wherein two wire clip members are bonded in an elastomeric material and placed within the recess of an adapter nose. When the pin is assembled, the spring clips apply a force to the pin to retain the pin in its assembled position Additionally, U.S. Pat. No. 4,096,653 issued June 27, 1978 to W. O. Kaarlela teaches a pin retainer that has an elastomeric material secured in a metal retainer. The retainer is placed, when assembled, in a recess of the adapter nose and upon assembly of the pin, the elastomeric material applies a biasing force to the pin to secure the pin in its assembled position.
Each of the above-noted U.S. patents teach a combination in which a retainer secures a pin or bar in its assembled position for retaining a tip on the adapter. However, each of these arrangements are limited in the amount of force that can be applied to the pin for holding the pin in its assembled position. When the above-noted arrangements are operated in more harsh conditions, the pin has a tendency to move against the biasing force of the retainer and come out. Consequently, the tip falls from the adapter resulting in major damage to the adapter nose upon further use.
U.S. Pat. No. 3,959,901 issued June 1, 1976 to Gene R. Klett teaches an arrangement having a split spring retainer located in a recess of the adapter nose and a pin for holding the tip on the adapter nose. The retaining force is applied by the interference fit between the spring retainer and the pin. This mechanism provides a pin retaining system that has a larger force acting on the pin to hold it in its assembled position. However, since the diameter of the spring retainer is close to the same diameter as the recess in which it is placed, complications are created. It has been determined that during operation forces encountered on the end of the tip are being transferred through the spring retainer to the adapter nose as opposed to the forces being applied through the pin itself. Consequently, the high forces acting on the spring retainer at times causes the spring retainer to open up, thus losing its frictional force on the pin and the pin falls out. Thus allowing the tip to fall off.
In order to offset the problem of forces being transferred through the spring retainer as noted above, the outside diameter of the spring retainer has been reduced to insure that during operation there is no physical contact between the diameter of the recess and the outside diameter of the spring retainer. By changing the outside diameter of the spring retainer, the problem of forces being transferred from the tip to retainer has been eliminated. However, the reduction of the outside diameter on the spring retainer creates an additional problem. Since the outside diameter of the retainer is small with respect to the diameter of the recess, the retainer, during assembly, sets low in the recess. When insertion of the pin is attempted, the inside diameter of the retainer is not lined up with the transverse bore of the nose. Consequently, the end of the pin hits the side of the retainer and does not allow the pin to enter the retainer. In order to offset this misalignment, a large chamfer was machined on the end of the pin. The large chamfer on the pin helped alleviate a degree of misalignment but required the pin to be longer. The chamfered end of the longer pin must extend beyond the outer surface of the tip to ensure proper retention. With the pin extending beyond the end of the tip, it is subjected to foreign objects and extensive wear during operation. Many times, foreign objects cause the pin to be pushed to one side. This allows one side of the tip to be loose on the adapter since the hole in the tip is interacting only with the chamfer of the pin.
British patent specification No. 1,518,824 published on July 26, 1978 and assigned to the assignee of the subject invention teaches a system having a retainer mechanism including a pin for insertion through respective holes in the tip and adapter nose and a torsion wire spring retainer substantially ecapsulated by an elastomeric material and adapted for insertion into a counterbore of the adapter nose. During assembly, the spring retainer exerts a force on the pin to hold the pin in its proper assembled position. Furthermore, in FIG. 4 the pin has a groove therein and upon assembly, the spring retainer is positioned in the groove to aid in pin retention.
The present invention is directed to overcoming one or more of the problems as set forth above.